Individuals with bipolar disorder (BD) are at high risk for chronic medical illnesses such as HIV infection. Few prospective studies have been conducted with persons with bipolar disorder and HIV infection (BD+/HIV+) despite their growing numbers, unique needs, and the possibility that these individuals may increase risk for HIV transmission through nonadherence to medications. Successful treatment of HIV infection requires managing complex antiretroviral (ARV) medication regimens, and comorbid bipolar disorder may be associated with an increased risk for medication nonadherence. Worse ARV medication adherence may lead to faster progression of HIV illness and hasten the development treatment resistant HIV strains. In addition to assessing the feasibility of recruiting a cohort of BD+/HIV+ individuals, the proposed study has two primary aims: 1) to describe the degree of adherence to ARV medications among BD+/HIV+ individuals as compared to individuals with HIV infection alone (BD-/HIV+), and 2) to determine the influence of various factors on ARV medication non-adherence among BD+/HIV+ individuals. To address these goals, we will recruit and assess 51 BD+/HIV+ outpatients and 51 HIV-infected individuals without bipolar disorder (BD-/HIV+). A comprehensive evaluation of adherence to ARV medication will be conducted, and the primary outcome variable will be percent adherence over 30 days as measured by Medication Event Monitoring System (MEMS). MEMS technology is widely used in the HIV-infection adherence literature, and provides detailed, objective, and comprehensive adherence data. To evaluate the possible predictors of poor medication adherence, we will also assess cognitive abilities, psychiatric symptoms, co-occurring substance use, and medication-related factors including adherence to psychotropic medications, complexity of medication regimen, and attitudes toward medications. Results from this study will provide needed information about 1) whether bipolar disorder increases risk for worse ARV medication adherence, and 2) the relative importance of risk factors for ARV nonadherence among BD+/HIV+ individuals. Furthermore, this study will help to inform the development of a targeted psychosocial intervention for the management of HIV infection among BD+/HIV+ individuals. More generally, the present study will provide useful information on the treatment of other chronic medical illnesses that may co-occur among patients with bipolar disorder. [unreadable] [unreadable] [unreadable] [unreadable]